Numerical Simulation Method for the Disaster Chain of Ice Lake Outburst Flood Induced by Landslide Tsunami

Abstract

The present invention discloses a numerical simulation method for the landslide-induced surge-triggered glacial lake outburst flood disaster chain, including a depth-averaged mixed flow model that couples water, coarse particles, fine particles, and gas phases based on the continuous medium mechanics method to obtain the data required for the numerical simulation method. This application combines the continuous medium mechanics theory, and through the continuous medium mechanics method, couples a depth-averaged mixed flow model of water, coarse particles, fine particles, and gas phases, and uses the finite difference method to realize the numerical simulation of the landslide-induced surge-triggered glacial lake outburst flood disaster chain. The numerical simulation method for the landslide-induced surge-triggered glacial lake outburst flood disaster chain of this application comprehensively considers the full-process coupling of the glacial lake outburst disaster chain from landslide movement to landslide into the lake triggering surges and then to surges triggering glacial lake outburst and flood evolution, and successfully realizes the full-process simulation of the landslide-induced glacial lake outburst flood disaster chain, providing technical support for the field of glacial lake outburst.

Description

Technical Field

[0001] The present invention belongs to the technical field of glacial lake outburst, and particularly relates to a numerical simulation method for the flood disaster chain induced by landslide-generated waves triggering glacial lake outburst. Background Art

[0002] Glacial lake outburst is a common natural disaster in alpine regions. Glacial retreat in alpine regions will form moraine lakes at the front of glaciers. A large number of landslides are often distributed around these alpine glacial lakes. When a landslide enters the lake, it has a strong impact on the lake water, thus inducing waves. When the waves reach the moraine dam, the moraine dam is cut by the scouring of the waves, and the glacial lake begins to burst. Once the glacial lake bursts, the outburst flood will pose a serious threat to the infrastructure and the lives of residents downstream of the glacial lake. At present, there is no numerical simulation method for the whole process coupling of this type of glacial lake outburst disaster chain. Summary of the Invention

[0003] The purpose of the present invention is to provide a numerical simulation method for the flood disaster chain induced by landslide-generated waves triggering glacial lake outburst, so as to solve the problem that there is no numerical simulation method for the whole process coupling of the glacial lake outburst disaster chain at present.

[0004] The embodiment of the present application is implemented as follows. For the numerical simulation method for the flood disaster chain induced by landslide-generated waves triggering glacial lake outburst, it includes: a depth-averaged mixed flow model based on the continuous medium mechanics method coupling four-phase media of water, coarse particles, fine particles and gas phase to obtain the data required for the numerical simulation method. The data includes at least one of topographic data, the position where the landslide starts, the volume and depth information of the landslide start, the initial content of coarse particles and fine particles in the landslide, the friction angle between the landslide and the bottom bed, the content of coarse particles and fine particles in the erodible channel where the landslide is located, the water depth distribution of the glacial lake, the roughness coefficient of the bottom bed for the wave and flood evolution, the content of coarse particles and fine particles in the moraine dam body, the characteristic particle size of coarse particles and the characteristic particle size of fine particles in the moraine dam body.

[0005] In some embodiments, the mixed flow motion control equation of the depth-averaged mixed flow model is:

[0006] ;

[0007] ;

[0008] ;

[0009] In the formula, is the mixed flow density, unit: ;

[0010] is the bottom bed resistance of the mixed flow along the direction, unit: ;

[0011] is the bed resistance along the direction in the mixed flow, unit: ;

[0012] is the flow depth of the mixed flow, unit: ;

[0013] is the elevation of the terrain required for numerical simulation, unit: ;

[0014] , is the discharge per unit width of the mixed flow along direction, unit: ;

[0015] , is the discharge per unit width of the mixed flow along direction, unit: ;

[0016] is the flow velocity along the direction of the mixed flow, unit: ;

[0017] is the flow velocity along the direction of the mixed flow, unit: ;

[0018] is the total erosion rate of the mixed flow, unit: ;

[0019] , is the acceleration of gravity, unit: ;

[0020] t is time, unit: s.

[0021] In some embodiments, in the mixed flow, the transport equations of water, fine particulate matter, coarse particulate matter and gas phase are:

[0022] ;

[0023] ;

[0024] ;

[0025] ;

[0026] In the formula, is the flow depth of the mixed flow, unit: ;

[0027] , is the discharge per unit width of the mixed flow along the direction, unit: ;

[0028] , is the discharge per unit width of the mixed flow along the direction, unit: ;

[0029] is the flow velocity of the mixed flow along the direction, unit: ;

[0030] is the flow velocity of the mixed flow along the direction, unit: ;

[0031] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0032] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0033] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0034] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0035] is the erosion rate of the water phase during the movement of the mixed flow, unit: ;

[0036] is the erosion rate of fine particle matter during the movement of the mixed flow, unit: ;

[0037] is the erosion rate of coarse particle matter during the movement of the mixed flow, unit: ;

[0038] is the erosion rate of air during the movement of the mixed flow, unit: ;

[0039] The air overflow rate in the mixed flow, unit: ;

[0040] , is the acceleration of gravity, unit: ;

[0041] t is time, unit: s.

[0042] In some embodiments, the evolution equation of the terrain is:

[0043] ;

[0044] In the formula, is the elevation of the terrain required for numerical simulation, unit: ;

[0045] is the total erosion rate of the mixed flow, unit: ;

[0046] t is time, unit: s.

[0047] In some embodiments, the expression of the mixed flow density is:

[0048] ;

[0049] In the formula, is the mixed flow density, unit: ;

[0050] , is the density of clear water, unit: ;

[0051] , is the density of coarse and fine particle materials, unit: ;

[0052] , is the density of air, unit: ;

[0053] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0054] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0055] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0056] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0057] In some embodiments, the expressions of the bed resistance of the mixed flow in the x - direction and y - direction are:

[0058] ;

[0059] ;

[0060] In the formula: is the mixed flow density, unit: ;

[0061] is the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless;

[0062] is the bed resistance of the mixed flow along the direction, unit: ;

[0063] is the bed resistance of the mixed flow along the direction, unit: ;

[0064] is the resistance of the mixture of fine-grained materials, water, and gas phase moving along the x direction, unit: ;

[0065] is the resistance of the mixture of fine-grained materials, water, and gas phase moving along the y direction, unit: ;

[0066] is the resistance of the coarse particles in the mixed flow along the direction, unit: ;

[0067] is the resistance of the coarse particles in the mixed flow along the direction, unit: ;

[0068] , is the acceleration due to gravity, unit: ;

[0069] is the Manning coefficient, unit: ;

[0070] , is the unit-width discharge of the mixed flow along the direction, unit: ;

[0071] , is the unit-width discharge of the mixed flow along the direction, unit: ;

[0072] is the flow velocity of the mixed flow along the direction, unit: ;

[0073] is the flow velocity of the mixed flow along the direction, unit: ;

[0074] is the flow depth of the mixed flow, unit: .

[0075] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0076] The expression of the conversion parameter when flood transitions to underwater saturated landslide or debris flow is:

[0077] ;

[0078] In the formula, is the conversion parameter when flood transitions to underwater saturated landslide or debris flow, unit: dimensionless;

[0079] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0080] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0081] is the critical total particle matter concentration at the boundary between underwater saturated landslide or debris flow and flood, unit: dimensionless, with a value of 0.18;

[0082] is the attenuation parameter when flood transitions to underwater saturated landslide or debris flow, unit: dimensionless unit, with a value of 13.8;

[0083] The motion resistances of the mixture of fine particle matter, water and gas phase along the x direction and y direction are respectively:

[0084] ;

[0085] and

[0086] ;

[0087] In the formula: is the motion resistance of the mixture of fine particle matter, water and gas phase along the x direction, unit: ;

[0088] is the motion resistance of the mixture of fine particle matter, water and gas phase along the y direction, unit: ;

[0089] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0090] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0091] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0092] is the unit-width discharge of the mixed flow along the direction, unit: ;

[0093] is the unit-width discharge of the mixed flow along the direction, unit: ;

[0094] is the flow velocity of the mixed flow along the direction, unit: ;

[0095] is the flow velocity of the mixed flow along the direction, unit: ;

[0096] is the flow depth of the mixed flow, unit: ;

[0097] , is the density of clear water, unit: ;

[0098] , is the density of coarse and fine particle materials, unit: ;

[0099] , is the density of air, unit: ;

[0100] is the suction stress between unsaturated fine particles, unit: ;

[0101] is the friction angle between unsaturated fine particle materials and the bottom bed in the mixed flow, unit: °;

[0102] is the cohesion of unsaturated fine particle materials, unit: ;

[0103] , , , , all of which are empirical coefficients;

[0104] is the conversion parameter from the resistance of unsaturated landslides to saturated landslides, dimensionless.

[0105] In some embodiments, the conversion parameter from the resistance of unsaturated landslides to saturated landslides is expressed as:

[0106] ;

[0107] In the formula, is the conversion parameter from the resistance of unsaturated landslides to saturated landslides, dimensionless;

[0108] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0109] is the critical gas-phase volume fraction when the landslide is designated as saturated by the present invention, with a value of 0.001, unit: dimensionless;

[0110] is the attenuation parameter for the conversion of the resistance from unsaturated landslides to saturated landslides, unit: dimensionless, with a value of 13.8;

[0111] The suction stress between unsaturated fine particles is expressed as:

[0112] ;

[0113] In the formula, is the suction stress between unsaturated fine particles, unit: ;

[0114] , are all empirical coefficients when calculating the suction stress, unit: dimensionless;

[0115] is the volumetric water content between fine particles, unit: dimensionless;

[0116] is the residual water content between fine particles, unit: dimensionless;

[0117] is the saturated water content between fine particles, unit: dimensionless;

[0118] is , unit: dimensionless;

[0119] The volumetric water content between fine particles is expressed as:

[0120] ;

[0121] In the formula, is the volumetric water content between fine particles, unit: dimensionless;

[0122] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0123] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0124] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0125] In some embodiments, the motion resistances of the coarse particles in the mixed flow along the x - direction and y - direction are respectively:

[0126] ;

[0127] ;

[0128] In the formula, is the motion resistance of the coarse particles in the mixed flow along the direction, unit: ;

[0129] is the motion resistance of the coarse particles in the mixed flow along the direction, unit: ;

[0130] is the density of the mixed flow, unit: ;

[0131] is the density of the mixture composed of fine particles, water and gas, unit: ;

[0132] is the unit - width flow rate of the mixed flow along the direction, unit: ;

[0133] is the unit - width flow rate of the mixed flow along the direction, unit: ;

[0134] is the mixed flow along Directional flow velocity, unit: ;

[0135] is the flow velocity of the mixed flow along direction, unit: ;

[0136] is the flow depth of the mixed flow, unit: ;

[0137] is the slope of the bottom bed of the mixed flow along direction, unit: °;

[0138] is the slope of the debris flow bottom bed along direction, unit: °;

[0139] is the friction angle between the coarse-grained material and the bottom bed in the mixed flow, unit: °;

[0140] is the volume fraction of the coarse particles in the mixed flow, unit: dimensionless;

[0141] is the turbulence coefficient of the coarse-grained material in the mixed flow, unit: ;

[0142] , is the acceleration due to gravity, unit: ;

[0143] , is the density of the fine-grained material, unit: ;

[0144] The density of the mixture composed of fine particles, water and gas The expression is:

[0145] ;

[0146] In the formula, is the density of the mixture composed of fine particles, water and gas, unit: ;

[0147] , is the density of clear water, unit: ;

[0148] , is the density of the fine-grained material, unit: ;

[0149] , is the density of air, unit: ;

[0150] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0151] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0152] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0153] In some embodiments, the total erosion rate of the mixed flow has the following expression:

[0154] ;

[0155] In the formula, is the total erosion rate of the mixed flow, unit: ;

[0156] is the flow depth of the mixed flow, unit: ;

[0157] is the density of the mixed flow, unit: ;

[0158] is the bed resistance of the mixed flow along the direction, unit: ;

[0159] is the bed resistance of the mixed flow along the direction, unit: ;

[0160] is the flow velocity of the mixed flow along the direction, unit: ;

[0161] is the flow velocity of the mixed flow along the direction, unit: ;

[0162] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0163] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0164] , is the acceleration due to gravity, unit: ;

[0165] is the ratio of pore water pressure to total pressure in the bed particle material, unit: dimensionless parameter;

[0166] , is the slope of the mixed-flow channel bed, unit: °;

[0167] is the slope of the bed along direction, unit: °;

[0168] is the slope of the bed along direction, unit: °;

[0169] is the friction angle of the bed particle material, unit: °;

[0170] is the cohesion of the bed particle material, unit: ;

[0171] is the terrain elevation of the ( )-th grid, unit: ;

[0172] is the terrain elevation of the ( )-th grid, unit: ;

[0173] is the terrain elevation of the ( )-th grid, unit: ;

[0174] is the grid size of the terrain in the direction, unit: ;

[0175] is the grid size of the terrain in the direction, unit: .

[0176] In some embodiments, the expressions for the erosion rates of the aqueous phase, gas phase, fine particle phase, and coarse particle phase in the mixed flow are:

[0177] ;

[0178] In the formula, is the total erosion rate of the mixed flow, unit: ;

[0179] is the gas-phase erosion rate during the mixed-flow movement, unit: ;

[0180] is the erosion rate of fine particulate matter during the mixed-flow movement, unit: ;

[0181] is the erosion rate of coarse particulate matter during the mixed-flow movement, unit: ;

[0182] is the erosion rate of the water phase during the mixed-flow movement, unit: ;

[0183] is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless;

[0184] is the volume fraction of fine particulate matter in the erodible gully bed, unit: dimensionless;

[0185] is the volume fraction of coarse particulate matter in the erodible gully bed, unit: dimensionless;

[0186] is the volume fraction of the water phase in the erodible gully bed, unit: dimensionless.

[0187] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0188] This application combines the theory of continuum mechanics and realizes the numerical simulation of the landslide-induced ice lake outburst flood disaster chain through a depth-averaged mixed-flow model that couples four-phase media of water, coarse particles, fine particles, and gas phase by means of continuum mechanics methods and uses the finite difference method. The numerical simulation method of the landslide-induced ice lake outburst flood disaster chain in this application comprehensively considers the whole process coupling of the ice lake outburst disaster chain from landslide movement to landslide into the lake inducing surges and then to surges inducing ice lake outburst and flood evolution, and successfully realizes the whole-process simulation of the landslide-induced ice lake outburst flood disaster chain, providing technical support for the field of ice lake outburst. BRIEF DESCRIPTION OF THE DRAWINGS

[0189] Figure 1 is the simulation result of a certain gully landslide-induced ice lake outburst in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0190] To make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0191] The technical solution of this application is as follows:

[0192] Please refer to Figure 1 , this application embodiment provides a numerical simulation method for the landslide-induced ice lake outburst flood disaster chain, including: based on the depth-averaged mixed flow model that couples water, coarse particles, fine particles and gas phases by the continuous medium mechanics method, obtaining the data required for the numerical simulation method, the data including at least one of topographic data, the location where the landslide starts, the volume and depth information of the landslide start, the initial content of coarse particles and fine particles in the landslide, the friction angle between the landslide and the bottom bed, the content of coarse particles and fine particles in the erodible channel where the landslide is located, the ice lake water depth distribution, the roughness coefficient of the bottom bed for the wave run-up and flood evolution, the content of coarse particles and fine particles in the moraine dam body, the characteristic particle size of coarse particles and the characteristic particle size of fine particles in the moraine dam body.

[0193] This application combines the continuous medium mechanics theory, and through the continuous medium mechanics method, couples the depth-averaged mixed flow model of water, coarse particles, fine particles and gas phases, and uses the finite difference method to realize the numerical simulation of the landslide-induced ice lake outburst flood disaster chain. The numerical simulation method of the landslide-induced ice lake outburst flood disaster chain in this application comprehensively considers the whole process coupling of the ice lake outburst disaster chain from landslide movement to landslide into the lake inducing wave run-up and then wave run-up inducing ice lake outburst and flood evolution, and successfully realizes the whole process simulation of the landslide-induced ice lake outburst flood disaster chain, providing technical support for the field of ice lake outburst.

[0194] In some embodiments, the mixed flow motion control equation of the depth-averaged mixed flow model is:

[0195] ;

[0196] ;

[0197] ;

[0198] In the formula, is the mixed flow density, unit: ;

[0199] is the bottom bed resistance of the mixed flow along the direction, unit: ;

[0200] is in the mixed flow along the The bottom bed resistance in the direction, unit: ;

[0201] is the flow depth of the mixed flow, unit: ;

[0202] is the elevation of the terrain required for numerical simulation, unit: ;

[0203] , is the discharge per unit width of the mixed flow along direction, unit: ;

[0204] , is the discharge per unit width of the mixed flow along direction, unit: ;

[0205] is the flow velocity of the mixed flow along direction, unit: ;

[0206] is the flow velocity of the mixed flow along direction, unit: ;

[0207] is the total erosion rate of the mixed flow, unit: ;

[0208] , is the acceleration due to gravity, unit: ;

[0209] t is time, unit: s;

[0210] In some embodiments, in the mixed flow, the transport equations of water, fine particulate matter, coarse particulate matter and gas phase are:

[0211] ;

[0212] ;

[0213] ;

[0214] ;

[0215] In the formula, is the flow depth of the mixed flow, unit: ;

[0216] , is the mixed flow along The single-width flow rate in the ;

[0217] , which is the single-width flow rate of the mixed flow along the direction, unit: ;

[0218] is the flow velocity of the mixed flow along the direction, unit: ;

[0219] is the flow velocity of the mixed flow along the direction, unit: ;

[0220] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0221] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0222] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0223] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0224] is the erosion rate of the water phase during the movement of the mixed flow, unit: ;

[0225] is the erosion rate of fine particle matter during the movement of the mixed flow, unit: ;

[0226] is the erosion rate of coarse particle matter during the movement of the mixed flow, unit: ;

[0227] is the erosion rate of air during the movement of the mixed flow, unit: ;

[0228] The air overflow rate in the mixed flow, unit: ;

[0229] , which is the acceleration due to gravity, unit: ;

[0230] t is time, unit: s;

[0231] In some embodiments, the evolution equation of the terrain is:

[0232] ;

[0233] In the formula, is the elevation of the terrain required for numerical simulation, unit: ;

[0234] is the total erosion rate of the mixed flow, unit: ;

[0235] t is time, unit: s.

[0236] In some embodiments, the expression of the density of the mixed flow is:

[0237] ;

[0238] In the formula, is the density of the mixed flow, unit: ;

[0239] , is the density of clear water, unit: ;

[0240] , is the density of coarse and fine particulate matter, unit: ;

[0241] , is the density of air, unit: ;

[0242] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0243] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0244] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0245] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0246] In some embodiments, the expressions of the bed resistance of the mixed flow in the x - direction and y - direction are:

[0247] ;

[0248] ;

[0249] In the formula: is the mixed flow density, unit: ;

[0250] is the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless;

[0251] is the bottom bed resistance of the mixed flow along direction, unit: ;

[0252] is the bottom bed resistance of the mixed flow along direction, unit: ;

[0253] is the movement resistance of the fine-grained material, water and gas mixture along the x direction, unit: ;

[0254] is the movement resistance of the fine-grained material, water and gas mixture along the y direction, unit: ;

[0255] is the resistance of the coarse particles in the mixed flow along direction, unit: ;

[0256] is the resistance of the coarse particles in the mixed flow along direction, unit: ;

[0257] , is the acceleration due to gravity, unit: ;

[0258] is the Manning coefficient, unit: ;

[0259] , is the unit discharge of the mixed flow along direction, unit: ;

[0260] , is the unit discharge of the mixed flow along direction, unit: ;

[0261] is the flow velocity of the mixed flow along direction, unit: ;

[0262] is the flow velocity of the mixed flow along Flow velocity in the direction, unit: ;

[0263] is the flow depth of the mixed flow, unit: ;

[0264] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless.

[0265] Furthermore, the expression of the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow is:

[0266] ;

[0267] In the formula, is the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless;

[0268] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0269] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0270] is the critical total particle matter concentration at the boundary between the underwater saturated landslide or debris flow and the flood, unit: dimensionless, with a value of 0.18;

[0271] is the attenuation parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless unit, with a value of 13.8;

[0272] It can be understood that when = 0.18, it represents that the conversion parameter of the flood is equal to 10 -6 , when is greater than 0.18 at this time, the movement resistance degrades to the movement resistance of the underwater saturated landslide (or debris flow), that is, the bed resistances of the mixed flow in the x - direction and y - direction are respectively and From this, the value of can be calculated and taken as 13.8.

[0273] Furthermore, the movement resistances of the mixture of fine particle matter, water and gas phase in the x direction and y direction are respectively:

[0274] ;

[0275] and

[0276] ;

[0277] In the formula: is the resistance of the mixture of fine particulate matter, water and gas phase moving in the x direction, unit: ;

[0278] is the resistance of the mixture of fine particulate matter, water and gas phase moving in the y direction, unit: ;

[0279] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0280] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0281] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0282] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0283] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0284] is the flow velocity of the mixed flow along the direction, unit: ;

[0285] is the flow velocity of the mixed flow along the direction, unit: ;

[0286] is the flow depth of the mixed flow, unit: ;

[0287] , is the density of clear water, unit: ;

[0288] , is the density of coarse and fine particulate matter, unit: ;

[0289] , is the density of air, unit: ;

[0290] is the suction stress between unsaturated fine particles, unit: ;

[0291] is the friction angle between unsaturated fine particulate matter and the bottom bed in the mixed flow, unit: °;

[0292] is the cohesion of the unsaturated fine particulate matter, unit: ;

[0293] , , , , all of which are empirical coefficients;

[0294] is the conversion parameter of the resistance from unsaturated landslide to saturated landslide, dimensionless.

[0295] Furthermore, the conversion parameter of the resistance from unsaturated landslide to saturated landslide has the following expression:

[0296] ;

[0297] In the formula, is the conversion parameter of the resistance from unsaturated landslide to saturated landslide, dimensionless;

[0298] is the volume fraction of air in the mixed flow, unit: dimensionless;

[0299] is the critical volume fraction of the gas phase when the landslide is designated as saturated by the present invention, with a value of 0.001, unit: dimensionless.

[0300] is the attenuation parameter of the resistance conversion from unsaturated landslide to saturated landslide, unit: dimensionless, with a value of 13.8;

[0301] It can be understood that when the gas phase volume fraction = 0.001, it represents that the conversion parameter of the resistance from unsaturated landslide to saturated landslide is equal to 10 -6 , when the gas phase volume fraction is greater than 0.001, the movement resistance degrades to the movement resistance of an unsaturated landslide (or debris flow), that is, the movement resistances of the mixture of fine particulate matter, water and gas phase along the x direction and the y direction are respectively and , from which the value of can be calculated to be 13.8.

[0302] Furthermore, the suction stress between unsaturated fine particles The expression is:

[0303] ;

[0304] In the formula, is the suction stress between unsaturated fine particles, unit: ;

[0305] , are all empirical coefficients when calculating the suction stress, unit: dimensionless;

[0306] is the volumetric water content between fine particles, unit: dimensionless;

[0307] is the residual water content between fine particles, unit: dimensionless;

[0308] is the saturated water content between fine particles, unit: dimensionless;

[0309] is , unit: dimensionless.

[0310] It can be understood that , is obtained from the experiments of unsaturated soil mass.

[0311] Furthermore, the volumetric water content between fine particles has the following expression:

[0312] ;

[0313] In the formula, is the volumetric water content between fine particles, unit: dimensionless;

[0314] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0315] is the volume fraction of fine particles in the mixed flow, unit: dimensionless;

[0316] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0317] Furthermore, the movement resistances of the coarse particles in the mixed flow in the x - direction and y - direction are respectively:

[0318] ;

[0319] ;

[0320] In the formula, is the movement resistance of coarse particles in the mixed flow along the direction, unit: ;

[0321] is the movement resistance of coarse particles in the mixed flow along the direction, unit: ;

[0322] is the density of the mixed flow, unit: ;

[0323] is the density of the mixture composed of fine particles, water and gas, unit: ;

[0324] is the unit-width flow rate of the mixed flow along the direction, unit: ;

[0325] is the unit-width flow rate of the mixed flow along the direction, unit: ;

[0326] is the flow velocity of the mixed flow along the direction, unit: ;

[0327] is the flow velocity of the mixed flow along the direction, unit: ;

[0328] is the flow depth of the mixed flow, unit: ;

[0329] is the slope of the bottom bed of the mixed flow along the direction, unit: °;

[0330] is the slope of the debris flow bottom bed along the direction, unit: °;

[0331] is the friction angle between the coarse particle material and the bottom bed in the mixed flow, unit: °;

[0332] is the volume fraction of coarse particles in the mixed flow, unit: dimensionless;

[0333] is the turbulence coefficient of the mixed-flow coarse particulate matter, unit: ;

[0334] , is the acceleration due to gravity, unit: ;

[0335] , is the density of the fine particulate matter, unit: .

[0336] Furthermore, the density of the mixture composed of fine particulate matter, water and gas is expressed as:

[0337] ;

[0338] In the formula, is the density of the mixture composed of fine particulate matter, water and gas, unit: ;

[0339] , is the density of clear water, unit: ;

[0340] , is the density of the fine particulate matter, unit: ;

[0341] , is the density of air, unit: ;

[0342] is the volume fraction of water in the mixed flow, unit: dimensionless;

[0343] is the volume fraction of fine particulate matter in the mixed flow, unit: dimensionless;

[0344] is the volume fraction of air in the mixed flow, unit: dimensionless.

[0345] Further, the total erosion rate of the mixed flow is expressed as:

[0346] ;

[0347] In the formula, is the total erosion rate of the mixed flow, unit: ;

[0348] is the flow depth of the mixed flow, unit: ;

[0349] is the density of the mixed flow, unit: ;

[0350] is the bed resistance of the mixed flow along the direction, unit: ;

[0351] is the bed resistance of the mixed flow along the direction, unit: ;

[0352] is the flow velocity of the mixed flow along the direction, unit: ;

[0353] is the flow velocity of the mixed flow along the direction, unit: ;

[0354] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0355] is the discharge per unit width of the mixed flow along the direction, unit: ;

[0356] , is the acceleration of gravity, unit: ;

[0357] is the ratio of pore water pressure to total pressure in the bed granular material, unit: dimensionless parameter;

[0358] , is the slope of the mixed flow channel bed, unit: °;

[0359] is the slope of the bed along the direction, unit: °;

[0360] is the slope of the bed along the direction, unit: °;

[0361] is the friction angle of the bed granular material, unit: °;

[0362] is the cohesion of the bed granular material, unit: ;

[0363] is the number of the Topographic elevation of the ()-th grid, unit: ;

[0364] is the topographic elevation of the ()-th grid, unit: ; ;

[0365] is the topographic elevation of the ()-th grid, unit: ; ;

[0366] is the grid size of the terrain in the direction, unit: ;

[0367] is the grid size of the terrain in the direction, unit: .

[0368] Furthermore, the expressions for the erosion rates of the aqueous phase, gas phase, fine particle phase, and coarse particle phase in the mixed flow are:

[0369] ;

[0370] where is the total erosion rate of the mixed flow, unit: ;

[0371] is the erosion rate of the gas phase during the movement of the mixed flow, unit: ;

[0372] is the erosion rate of the fine particle material during the movement of the mixed flow, unit: ;

[0373] is the erosion rate of the coarse particle material during the movement of the mixed flow, unit: ;

[0374] is the erosion rate of the aqueous phase during the movement of the mixed flow, unit: ;

[0375] is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless;

[0376] is the volume fraction of the fine particle material in the erodible gully bed, unit: dimensionless;

[0377] is the volume fraction of coarse-grained materials in the erodible gully bed, unit: dimensionless;

[0378] is the volume fraction of the water phase in the erodible gully bed, unit: dimensionless.

[0379] Experimental example

[0380] A certain gully landslide is about 150 m long, 70 m wide, and about 60 m thick, with a volume of approximately 1.1 million m³. There is an ice lake downstream of the landslide, and the elevation difference from the landslide location to the surface of the ice lake is approximately 240 m. The initial volume fraction of coarse-grained materials in the landslide body is 35%, the initial volume fraction of fine-grained materials is 25%, and the initial volume fraction of water is 5%. The friction angle between the coarse-grained materials in the mixed flow and the bottom bed is 30°, the friction angle between the unsaturated fine-grained materials in the mixed flow and the bottom bed is 25°, the empirical coefficient = 0.1, the empirical coefficient = 0.8, the turbulence coefficient of the coarse-grained materials is taken as 30.0 , the Manning roughness coefficient of the breach flood is taken as 0.05 ; the air overflow rate in the mixed flow is 0.05 , the volume fraction of the gas phase in the erodible gully bed is 0.15; the volume fraction of the fine-grained materials in the erodible gully bed is 0.24; the volume fraction of the coarse-grained materials in the erodible gully bed is 0.36; the volume fraction of the coarse-grained materials in the erodible gully bed is 0.25; the rheological empirical coefficient of the liquid-phase slurry is taken as , , , , the ratio of the pore water pressure to the total pressure in the bottom bed granular materials is 0.8 (unit: dimensionless parameter), the friction angle of the bottom bed granular materials is taken as 32°, the cohesion of the bottom bed granular materials is taken as 12500 , the grid size of the terrain in the direction is 12.5 m, the grid size of the terrain in the direction is 12.5 m, the density of clear water , the density of the coarse-grained and fine-grained materials , the density of air . Input the above parameters into the depth-averaged mixed flow model for calculation, and obtain the dynamic distribution results of the landslide depth and the ice lake flood depth at different times, and the results are as shown in Figure 1 .

[0381] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. Numerical simulation method for the disaster chain of ice lake outburst flood induced by landslide surge, characterized in that, Including: A depth-averaged mixed flow model that couples water, coarse particles, fine particles, and gas phases based on the continuum mechanics method to obtain the data required for numerical simulation methods. The data includes at least one of topographic data, the location of landslide initiation, the volume and depth information of landslide initiation, the initial content of coarse and fine particle materials in the landslide, the friction angle between the landslide and the bed, the content of coarse and fine particle materials in the erodible channel by the landslide, the distribution of ice lake water depth, the bed roughness coefficient of surge and flood evolution, the content of coarse and fine particle materials in the moraine dam, the characteristic particle size of coarse particles in the moraine dam, and the characteristic particle size of fine particles. The motion control equation of the mixed flow in the depth-averaged mixed flow model is: ； ； ； In the formula, is the mixed flow density, unit: ; For the bed resistance of the mixed flow along direction, unit: ; For the bottom bed resistance along the direction in the mixed flow, unit: ; is the flow depth of the mixed flow, unit: ; is the elevation of the terrain required for numerical simulation, unit: ; , is the unit-width flow rate of the mixed flow along direction, unit: ; , which is the unit-width flow rate of the mixed flow along direction, unit: ; For the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the total erosion rate of the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s; In the mixed flow, the transport equations of water, fine particle materials, coarse particle materials, and gas phases are: ； ； ； ； In the formula, is the flow depth of the mixed flow, unit: ; , is the unit-width flow rate of the mixed flow along the direction, unit: ; , is the unit-width flow rate of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the erosion rate of the aqueous phase during the mixed-flow movement, unit: ; is the erosion rate of fine particulate matter during the mixed-flow movement, unit: ; is the erosion rate of coarse particulate matter during the mixed flow movement, unit: ; is the air erosion rate during the mixed flow movement, unit: ; Air overflow rate in the mixed flow, unit: ; , is the acceleration due to gravity, unit: ; t is time, unit: s; The evolution equation of the terrain is: ； In the formula, is the elevation of the terrain required for numerical simulation, unit: ; is the total erosion rate of the mixed flow, unit: ; t is time, unit: s.

2. The numerical simulation method for the landslide-induced surge-triggered glacial lake outburst flood disaster chain according to claim 1, characterized in that The expression of the mixed flow density is: ； In the formula, is the mixed flow density, unit: ; , which is the density of clear water, unit: ; , is the density of the coarse and fine particulate matter, unit: ; , is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

3. The numerical simulation method for the landslide-induced ice lake outburst flood disaster chain according to claim 1, characterized in that, The expressions of the bed resistance of the mixed flow in the x and y directions are: ； ； In the formula: is the mixed flow density, unit: ; It is the conversion parameter when flood transitions to underwater saturated landslide or debris flow, unit: dimensionless; For the bottom bed resistance of the mixed flow along direction, unit: ; For the bottom bed resistance in the direction of in the mixed flow, unit: ; is the resistance to the movement of the fine particulate matter, water and gas mixture in the x direction, unit: ; The resistance to the movement of the fine particulate matter, water and gas mixture in the y direction, unit: ; For the resistance of coarse particles in the mixed flow along the direction, unit: ; For the resistance of coarse particles in the mixed flow along the direction, unit: ; , is the acceleration due to gravity, unit: ; is the Manning coefficient, unit: ; , is the discharge per unit width of the mixed flow along direction, unit: ; , which is the unit-width flow rate of the mixed flow along direction, unit: ; For the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the flow depth of the mixed flow, unit: ; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; The expression of the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow is: ； In the formula, is the conversion parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; The critical total particulate matter concentration that demarcates underwater saturated landslides or debris flows from floods, unit: dimensionless, with a value of 0.18; It is the attenuation parameter when the flood transitions to an underwater saturated landslide or debris flow, unit: dimensionless unit, with a value of 13.8; The moving resistances of the fine particulate matter, water and gas mixture along the x direction and y direction are respectively: ； and ； In the formula: is the resistance of the fine particulate matter, water and gas mixture moving in the x direction, unit: ; is the resistance to the movement of the fine particulate matter, water and gas mixture in the y direction, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; is the discharge per unit width of the mixed flow along direction, unit: ; is the unit-width flow rate of the mixed flow along direction, unit: ; For the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the flow depth of the mixed flow, unit: ; , is the density of clear water, unit: ; , is the density of the coarse and fine particulate matter, unit: ; , which is the density of air, unit: ; is the suction stress between unsaturated fine particles, unit: ; is the friction angle between unsaturated fine particulate matter and the bottom bed in the mixed flow, unit: °; is the cohesion of unsaturated fine-grained materials, unit: ; , , , , all of which are empirical coefficients; is the conversion parameter of the resistance from unsaturated landslide to saturated landslide, dimensionless.

4. The numerical simulation method for the landslide-induced ice lake outburst flood disaster chain according to claim 3, characterized in that Resistance conversion parameter from unsaturated landslide to saturated landslide The expression is as follows: ； In the formula, is the conversion parameter of the resistance from unsaturated landslide to saturated landslide, dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless; It is the critical volume fraction of the gas phase when the landslide is saturated, with a value of 0.001 and the unit: dimensionless; is the attenuation parameter for the conversion of the resistance from unsaturated landslide to saturated landslide, unit: dimensionless, with a value of 13.8; Suction stress between unsaturated fine particles The expression is as follows: ； In the formula, is the suction stress between unsaturated fine particles, unit: ; , Both are empirical coefficients when calculating the suction stress, unit: dimensionless; is the volumetric water content between fine particles, unit: dimensionless; is the residual moisture content between fine particles, unit: dimensionless; is the saturated water content between fine particles, unit: dimensionless; For , unit: dimensionless; Volumetric water content between fine particles The expression is as follows: ； In the formula, is the volumetric water content between fine particles, unit: dimensionless; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

5. The numerical simulation method for the landslide-induced ice lake outburst flood disaster chain according to claim 4, wherein The motion resistances of the coarse particles in the mixed flow in the x and y directions are respectively: ； ； In the formula, is the motion resistance of the coarse particles in the mixed flow along direction, unit: ; The movement resistance of coarse particles in the mixed flow along the direction, unit: ; is the mixed flow density, unit: ; The density of the mixture composed of fine particles, water and gas, unit: ; is the unit-width flow rate of the mixed flow along the direction, unit: ; is the unit-width flow rate of the mixed flow along the direction, unit: ; For the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; is the flow depth of the mixed flow, unit: ; For the slope of the mixed-flow bottom bed along the direction, unit: °; is the slope of the debris flow bed along the direction, unit: °; is the friction angle between the coarse particulate matter and the bottom bed in the mixed flow, unit: °; is the volume fraction of coarse particles in the mixed flow, unit: dimensionless; is the turbulence coefficient of the mixed-flow coarse particulate matter, unit: ; , is the acceleration due to gravity, unit: ; , is the density of fine particulate matter, unit: ; The density of the mixture composed of fine particles, water and gas is expressed as: ； In the formula, is the density of the mixture composed of fine particles, water and gas, unit: ; , is the density of clear water, unit: ; , which is the density of fine particulate matter, unit: ; , which is the density of air, unit: ; is the volume fraction of water in the mixed flow, unit: dimensionless; is the volume fraction of fine particles in the mixed flow, unit: dimensionless; is the volume fraction of air in the mixed flow, unit: dimensionless.

6. The numerical simulation method for the landslide-induced ice lake outburst flood disaster chain according to claim 5, characterized in that Total erosion rate of mixed flow The expression is as follows: ； In the formula, is the total erosion rate of the mixed flow, unit: ; is the depth of the mixed flow, unit: ; is the mixed flow density, unit: ; For the bottom bed resistance of the mixed flow along the direction, unit: ; For the bed resistance of the mixed flow along the direction, unit: ; For the flow velocity of the mixed flow along direction, unit: ; is the flow velocity of the mixed flow along direction, unit: ; For the unit-width flow rate of the mixed flow along the direction, unit: ; is the unit-width flow rate of the mixed flow along direction, unit: ; , is the acceleration due to gravity, unit: ; is the ratio of pore water pressure to total pressure in the bottom bed granular material, unit: dimensionless parameter; , which is the slope of the mixed-flow channel bed, unit: °; For the slope of the bottom bed edge Direction, unit: °; For the slope of the bottom bed along the direction, unit: °; is the friction angle of the bottom bed granular material, unit: °; is the cohesion of the bottom bed granular material, unit: ; is the terrain elevation of the -th grid, unit: ; is the terrain elevation of the -th grid, unit: ; For the terrain elevation of the -th grid, unit: ; is the grid size in the direction, unit: ; is the grid size in the direction, unit: .

7. The numerical simulation method for the landslide-induced surge-triggered glacial lake outburst flood disaster chain according to claim 6, characterized in that The expressions of the erosion rates of the water phase, gas phase, fine particle phase, and coarse particle phase in the mixed flow are: ； In the formula, is the total erosion rate of the mixed flow, unit: ; is the gas phase erosion rate during the mixed flow movement, unit: ; is the erosion rate of fine particulate matter during the mixed-flow movement, unit: ; is the erosion rate of coarse particulate matter during the mixed-flow movement, unit: ; is the erosion rate of the aqueous phase during the mixed-flow movement, unit: ; is the volume fraction of the gas phase in the erodible gully bed, unit: dimensionless; is the volume fraction of fine particulate matter in the erodible gully bed, unit: dimensionless; is the volume fraction of coarse particulate matter in the erodible gully bed, unit: dimensionless; is the volume fraction of the aqueous phase in the erodible gully bed, unit: dimensionless.

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